code: def get_env_variable_by_name(name):
      """get env variable by name"""
      try:
          env_var = os.environ[name]
          log.debug(f"env_variable: {env_var}")
          return str(env_var)
      except Exception as e:
          log.debug(f"fail to get env variables, error: {str(e)}")
          return None
  
file_path: milvus/tests/python_client/chaos/chaos_commons.py
imports: import os
  import threading
  import time
  import glob
  from chaos import constants
  from yaml import full_load
  from utils.util_log import test_log
  from delayed_assert import expect
  import pytest
label_desc: Use image node_id 6 for calling a global function with example usage: get_env_variable_by_name(name) and returns: str, None